Roller bearing assemblies comprised of a plurality of cylindrical rollers arranged in a circle and supported by a roller cage supporting the rollers at either end of the bearing assembly are well known. Most such bearing assemblies are designed to transfer radial but not axial loading. Bearings which are designed for the transfer of both radial as well as axial loads are known as thrust bearings. Known thrust bearings rely, at least in part, upon the rollers themselves to transfer axial loads on the assembly.
The prior art, such as discussed below, discloses various ways to decrease the friction between the roller bearings and the bearing cage or shaft caused by radial loads. While these designs may be suitable to reduce the roller wear caused by radial loads placed on rollers, none shows how to prevent roller wear caused by axial loads.
U.S. Pat. No. 91,695 (Wilcox) discloses a bearing cage which consists of several sections, which form a circle when assembled in a shafting box.
U.S. Pat. No. 197,289 (Peters) shows a typical roller bearing cage of rigid design wherein the two parallel ends of the cylindrical shaped cage are held together by connecting rods. The rollers are mounted on axles extending between the ends of the cage.
U.S. Pat. No. 458,520 discloses typical roller bearings and cage, wherein the rollers are mounted on pins which extend from both ends of the cage, rather than on continuous axles.
U.S. Pat. No. 664,821 (Perkins) discloses locking devices to keep the ends of a roller bearing cage from separating once assembled and in operation.
U.S. Pat. No. 681,549 (Holt) discloses the use of segmented rollers, wherein several separate rollers share the same axis of rotation, but are capable of independent rotation.
U.S. Pat. No. 869,217 (Stratton) discloses the placement of spacing rollers in between the bearing rollers. The ends of the spacing rollers and bearing rollers are beveled to reduce the frictional contact with the ends of the cage. The spacing rollers do not contact either inner surface of the roller bearing cage, or the shaft or axle upon which the cage is mounted.
U.S. Pat. No. 2,782,080 (Norton) discloses cylindrical rollers which taper off in a conical fashion near their ends then form a pin or tongue. The rollers are mounted within the cage by fitting the pins at the ends of the rollers into corresponding openings in the ends of the cage. Norton also shows that the bearing cage can be constructed as a split ring which can be easily closed and fitted around a shaft.
U.S. Pat. No. 2,950,151 (Clark et al.) discloses cylindrical rollers which are held in place without the use of axles or pins. Fingers separate the roller bearings while holding the bearings in place. The fingers also serve to connect the two ends, or collars of the bearing cage.
U.S. Pat. No. 3,647,273 (Phaffenberger) discloses spacing bars with curved surfaces which come into contact with, and separate the roller bearings. The spacing bars also connect the opposite ends of the bearing assembly.
U.S. Pat. No. 3,944,307 (Bingle) discloses a bearing cage design suitably manufactured out of plastics in which the rods or ribs which connect the two opposite ends of the bearing cage are at one end integrally molded to the cage. The other end of these ribs will be welded to the bearing cage once it is assembled.
The present invention is therefore intended to prevent the axial loads from being absorbed by the rollers since shear stresses on the roller surface results in inordinate wear and requires more frequent replacement of the rollers.